Tent-free apparatus for particulate contamination control

ABSTRACT

A tent-free technique, system, and apparatus for effecting protection of humans from airborne asbestos and other particulate contamination is disclosed. It comprises a first transparent cowling means operatively associated with drilling means and at least one filtration unit flow connected therewith. The first cowling means comprises two members slidably disposed relative to one another, with the first member thereof being more or less substantially fixed relative to the drilling means housing and the second member adapted to be more or less substantially fixed temporarily to the plane of the material first engaged by the drill bit. A second cowling means, also flow connected to said filtration unit, is operatively associated with the instant apparatus and more or less substantially fixed temporarily to the plane of the material lastly engaged by said drill bit. A third cowling means is operatively associated with sawing means and fixed relative to the housing thereof and adapted for enclosing the saw blade. The cowlings can be made and retrofitted into existing drills and/or saws. The drill with first cowling member attached is positioned relative to said second member and inserted thereinto and the drill bit is properly positioned by means of the transparent nature of the resulting composite first cowling. Said second cowling means is placed onto the desired location on the opposite side of the material to be drilled, usually by hand holding effected by the drill operator helper and the drilling operation is commenced. The sawing means is utilized with said third cowling attached and with said second cowling in place on the opposite side of said material.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes without the payment to me ofany royalty therefor.

This is a division of application Ser. No. 07/546,266, filed June 26,1990 now U.S. Pat. No. 5,034,041.

INTRODUCTION

The present invention relates to a new, novel, safe and relativelysimple and inexpensive, as well as highly efficient method and means fordealing with the serious dangers associated with the inhalation ofparticulate material suspended in the air environment generallysurrounding human operators who are called upon from time to time torepair, maintain, machine, cut, or otherwise modify structurescontaining asbestos or other dangerous and highly friable materials,including ebony-asbestos boards upon which are mounted, or will be latermounted, a wide variety of electrical components. It is well know thatany machining operation performed on such materials will give rise to anair-particulate suspension classified as a carcinogenic hazard to humansand animals, which suspension will encompass both the immediate areajuxtaposed said machining operation as well as the surrounding areas. Inthe instance of machining materials containing asbestos, it is welldocumented that the resulting disturbances will produce an area highlycontaminated with very fine particles comprised of fibers (includingthose less than several tenths of a micron in diameter) which may remainsuspended in the surrounding air for several days or more. Likewise,disturbances, including drilling, sawing, and the like of a variety ofother highly friable materials will oftentimes produce an environmentcomprised of highly dangerous and offending air suspended particulatecontamination.

Accordingly, in order to ensure the requisite degree of protection forthe workers who are called upon to effect such machining operations, ithas heretofore been necessary for such persons to wear protectiveclothing and to use appropriate breathing/filtering apparatus. As iswell appreciated by those operators who have had the occasion to dressin such protective suits, same are very uncomfortable in which to workand are extremely awkward when it is necessary to perform operationsrequiring any substantial degree of manual dexterity. In addition, inorder to protect the surrounding areas not immediately juxtaposed suchdisturbed area, and more particularly the persons who need to worktherein during periods of time coincident with, or shortly after suchdrilling and/or sawing or the like, such areas generally surrounding theimmediate work area must be sealed off and physically isolated from suchdisturbed environment. This isolation is oftentimes accomplished by theerection of "tents" usually comprised of thin plastic film. Moreover, inorder to fully ensure that the airborne asbestos fibers or otherdangerous particulates remain so isolated and do not find their way outof discontinuities in such tents, such as apertures provided foroperator ingress/egress, the resulting tent must be maintained with anegative pressure effected by utilization of air filtration units flowconnected with such tent enclosure. Even such precautions are oftentimesinadequate and require in combination therewith the utilization ofdecontamination chamber areas as well as mechanical sealing means forutilization with or over said ingress/egress apertures, which sealingmeans may include water filled troughs or other specially designedbarriers and flaps.

As is appreciated by those skilled in this art, there are oftentimesinstances wherein machine operations are to be performed on a variety ofin-place support units, including vertically disposed ebony-asbestosboards contained in electric utility switch houses and otherdistribution structures. Although modifications thereto usually requireonly minimal drilling and/or cutting prior to the actual placement ofadditional or replacement components, all of the above precautions haveheretofore been necessary in order to ensure the health and safetyconsiderations due the workers involved and required by various OSHArequirements. Thusly, both the time and resulting costs, which arenormally associated with such otherwise simple tasks, are greatlyexaggerated.

The present invention overcomes the many undesirable restrictions andcharacteristics of the best available and currently practiced state ofthe art relating to the serious dangers associated with personsbreathing such particulate contaminated air; as described supra, andeliminates the requirements for both the use of full protectiveclothing, by persons called upon to perform such disturbances uponasbestos containing materials, and more importantly the requirement toconstruct protective enclosures, including tents around the work area.

As indicated herein, a principal feature of the instant inventionincorporates the use of a plurality of cowling means which are utilizedto effect barriers between the source generating a high degree ofoffending particulate contamination, such as drill bits or saw bladesthat, respectively, provide apertures or cuts in materials such asasbestos or asbestos containing boards or the like, which particulatecontamination normally would become airborne and quickly spreadthroughout the area in which such machine operations occur, and suchsurrounding are that otherwise would be environmentally in communicationwith such source. Such cowling means generally are elongated and may beof a number of forms and shapes, including cylindrical for the best andmost efficient resistance to air pressure differential forces appliedthereto. They may be constructed of a variety of materials includingmetal, or more preferably plastic of the high impact type. Generally,they are shroud-like, comprised of relatively thin material in order toreduce the weight added by the use thereof, and are at least partiallyconstructed of transparent material to facilitate orientation by theoperator, of the specific machine tool; e.g., drill bit, saw blade,etc., relative to the target work area. Although in the instances hereindescribed, the operator is human; situations in which a robotic deviceis substituted for a human are also contemplated, albeit, the necessaryprotection would be primarily for the benefit of persons occupying theadjacent areas, etc. Although generally elongated, hollow, and free ofobstacles or interior structures, in order to facilitate the free flowof sweep air therethrough, they may be provided with interiors molded orotherwise shaped to direct or otherwise streamline such airflow. Thus,whenever the term "cowling" or "cowling means" is used herein it isintended and understood that such terms apply to, or describe such typesof structures or apparatus.

As also indicated herein, the instant invention comprises apparatus andsystems as well as a process for the practice thereof which is tent-freein the sense that no structures, such as tents comprised of relativelythin membranes of plastic material or the like are, or need to beerected over or about the area surrounding both the source generatingsuch a high degree of offending particulate contamination and the arearequired for manipulation by the human operators who are called upon,from time to time to perform the required machine operations. Examplesof requirements for such tent structures, which the present inventionsubstantially eliminates, may be found in the teaching of U.S. Pat. No.4,604,111, Natale, Aug. 5, 1986, elsewhere herein incorporated byspecific reference thereto. Thus, whenever the term "tent-free" is usedherein, it is intended and understood that such term applies to ordescribed apparatus or systems, as well as the practice of processeswhich eliminate the use or requirement for use or utilization of suchtypes of structures or apparatus over the immediate work area as well asthe generally surrounding work area normally occupied by human operatorsand attendant equipment which may be used in the performance of suchmodifications/machine operations.

As also indicated herein, the instant invention comprises apparatus andsystems as well as a process for the practice thereof which oftentimesperforms such modifications, including drilling and sawing on plate-likemembers comprised of asbestos, asbestos containing materials, or thelike and which members are oftentimes characterized as being friablesuch that any substantial mechanical disturbances resulting from suchdrilling and/or sawing gives rise to the incidence of copious amounts ofvery fine or small particulates, including fibers in the case ofasbestos boards, which quickly become airborne and remain so forsubstantial periods of time. Such plate-like members oftentimes take theform and shape of relatively thin and flat boards which may have avariety of electrical components mounted thereon and oftentimes aredisposed in generally vertical orientations, as found in electricalutility substations and switch houses. However, they may take otherforms and shapes, including being provided with sides (top and bottomwhen horizontally disposed) which are not substantially parallel to oneanother. There may also be instances wherein said members take formswhich can more accurately be described as block-like. Thus, whenever theterm "plate-like" is used herein, it is intended and understood thatsuch term applies to or describes apparatus of such construction ortype.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to methods and means for effectingprotection of humans from the deleterious effects of airborne asbestosand other particulate contamination and involves the use of severalspecially designed, partially or wholly transparent cowling meansoperatively associated with drilling and/or sawing means. The first andsecond of three such cowling means are operatively associated with atleast one filtration unit flow connected therewith and with a blower topull air into the specially designed cowlings and thence into thefiltration unit wherefrom the resulting filtered air is exhausted to theatmosphere. In order to accommodate the travel of the drill bit, thefirst cowling means operatively associated with said drilling meanscomprises two members slidably disposed relative to one another, withthe first member thereof being more or less substantially fixed relativeto the drill housing and the second member adapted to be fittedtemporarily to the target side of the mounting board or other member tobe drilled. In the preferred embodiment of the instant invention, saidsecond member of said first cowling means is provided with means foreffecting the flow connection with said at least one filtration unit.Normally, a second cowling means, also flow connected to said filtrationunit, is operatively associated with the instant apparatus and is fittedtemporarily (usually hand held by the operator or helper) to the side ofthe material which is opposite to that first targeted for engagementwith the drill bit of said drilling means. A third cowling means, alsoflow connected to said filtration unit, is operatively associated withsawing or cutting means, which sawing means may be utilized after holesare drilled in the mounting board to cut therebetween. The third cowlingmeans is generally fixed relative to the housing of said saw. One end ofsaid third cowling means is open and adapted to fit over the base plateof the saw, normally of the saber type, and the aperture represented bysaid open end defines a plane substantially parallel with the plane ofthe target board. Likewise, one end of the second cowling is generallyopen ended, with the plane defined by said aperture or open end, alsodisposed generally parallel with such board. It is important that allthree cowlings be constructed of material that is stiff, and/orresilient enough to withstand the substantial pressures that may bedeveloped therearound due to the pressure differential developed byoperation of the associated filtration unit. It is also important to theefficient and effective operation of the instant invention that allthree such cowling members or units be at least partially constructed ofmaterial which is transparent, thereby enabling the drill or sawoperator to observe the positions of either the drill bit or saw bladerelative to the target and to enable such operator to easily and readilyeffect proper orientation and/or positioning therebetween. It will alsobe appreciated that provisions may be made such that the flowconnections with the at least one filtration unit and the first andthird cowling means are arranged or constructed such that they are, orcan be releasably connected therewith. In such manner, after the holesare drilled and the drill is put aside, the vacuum hose connected to thesecond member of the first cowling means, may be removed therefrom andconnected, with the aid of suitable connecting means, to said thirdcowling means. Also, in the preferred embodiment of the instantinvention the second cowling means and the vacuum hose operativelyassociated therewith, which is normally used on the backside of theboard or plate to be drilled and/or sawed to capture particulatematerial forced therethrough by either the bit or blade, is utilized inseparate combinations with either the drill or the saw. Accordingly, theusually is no need to effect a disconnection between said second cowlingmeans and said at least one filtration unit. Thus, either three separatevacuum hoses may be used, or more preferably two vacuum hoses areutilized with a switching between the first and third cowling meansbeing effected by releasable connecting means, if and when it is deemeddesirable to follow the drilling procedure with a sawing operation. Aswill also be seen, two or more subhoses may be utilized to connect withsaid third cowling means and thence to a manifold or like device to joinin flow connection with the other hose(s), usually via a trunk line, tothe filtration unit.

2. Description of the Prior Art

As has been noted above, numerous prior art disclosures and practiceshave been incorporated into currently used procedures representing manyof those taught and disclosed in a plethora of methods and/or means forameliorating the deleterious health and personal safety considerationsnormally encountered in the removal and/or modification of structures orsubstructures constructed of materials comprising or containing asbestosor other highly friable materials which are classified as being, orpresenting a carcinogenic hazard to humans.

With reference to the state of the prior art as same relates to theutilization of numerous tent-like enclosures erected or otherwiseconstructed over and about work areas within which asbestos, or asbestoscontaining materials are to be drilled, sawed, or otherwise machined,and more specifically to the utilization of negative pressures incombination therewith, and still more particularly to variousmodifications thereof in combination with a variety of speciallydesigned ingress/egress aperture closure means, attention is directed toU.S. Pat. No. 4,604,111, Natale, Aug. 5, 1986, the teachings of which,along with the prior art disclosed therein, are hereby, herewith, andherein incorporated by means of this specific reference thereto.

A comparison of such prior art teachings with the disclosure of theinstant invention will reveal that the instant improvement over samecompletely eliminates the requirement or necessity of utilizing a tentor like structure to be erected over or about the work area whenasbestos type materials are to be drilled, sawed, or otherwise machined.Perhaps of equal importance, the practice of the instant inventioneliminates the requirement for wearing or the necessity of utilizingfull suit protective clothing and in-line respiratory devices in suchwork areas during the conduct of such operations.

SUMMARY OF THE INVENTION

The instant invention relates to a vastly improved technique, includingmethods and means for containing, lowering, and essentially eliminatingthe serious dangers associated with the inhalation of particulatematerial suspended in the air environment generally surrounding humanoperators who are called upon from time to time to repair, maintain,machine, drill, cut, or otherwise modify structures containing asbestosor other dangerous and highly friable materials, includingebony-asbestos boards upon which are mounted, or will be later mounted awide variety of electrical components. It is well know that anymachining operation performed on such materials will give rise to anair-particulate suspension classified as a carcinogenic hazard to humansand animals, which suspension will encompass both the immediate areajuxtaposed said machining operation as well as the surrounding areas. Ininstances of machining materials containing asbestos, it is welldocumented that the resulting disturbances will produce an area highlycontaminated with very fine particles comprised of fibers (includingthose less than several tenths of a micron in diameter) which may remainsuspended in the surrounding air for several days or more. Likewise,severe mechanical disturbances, including drilling, sawing, and thelike, of a variety of other highly friable materials will oftentimesproduce an environment comprised of highly dangerous and offending airsuspended particulate contamination.

OBJECTS OF THE INVENTION

It is therefore the principal object of the present invention to developa new, tent-free method and means for effecting protection of humansfrom fine fibers of asbestos or certain other carcinogenic materialswhich are oftentimes rendered airborne due to substantial mechanicaldisturbances effected on materials constructed of an/or containing suchcarcinogenics.

Another object of the present invention is to provide tent-free methodsand means whereby asbestos or asbestos containing boards, panels, andthe like including ebony mounting panels oftentimes found in electricalutility substations can be drilled and/or cut by human operators withoutrequiring the erection and maintenance of an environmental enclosure andbarrier over the work area to seal said area from human workersoccupying adjacent areas.

Still another object of the present invention is to provide tent-freemethods and means whereby asbestos and asbestos containing boards,panels, and the like including ebony mounting panels oftentimes found inelectrical utility substations can be drilled and/or cut by humanoperators without requiring the erection and maintenance of anenvironmental enclosure and barrier over the work area to seal said areafrom human workers occupying adjacent areas; and wherein the operatorsof such drills or saws are required only to wear half-face respiratorsrather than protective clothing and cumbersome air line masks.

A still further object of the present invention is to provide tent-freemethods and means whereby asbestos or asbestos containing boards,panels, and the like including ebony mounting panels oftentimes found inelectrical utility substations can be drilled and/or cut by humanoperators without requiring the erection and maintenance of anenvironmental enclosure and barrier over the work area to seal said areafrom human workers occupying adjacent areas; wherein the operators ofsuch drills or saws are required only to wear half-face respiratorsrather than protective clothing and cumbersome air line masks; andwherein savings realized in reduced set-up and take-down time effectedby the tent-free nature thereof are further complimented bysubstantially reduced contamination of the areas that normally would beenclosed in the tent enclosure currently used in the best availableprior art methods and thereby effectively reduces total clean-up time aswell as resulting exposure of persons to the particulate contaminatedair spread throughout the confines of the tented area.

Still another object of the present invention is to provide tent-freemethods and means whereby asbestos or asbestos containing boards,panels, and the like including ebony mounting panels oftentimes found inelectrical utility substations can be drilled and/or cut by humanoperators without requiring the erection and maintenance of anenvironmental enclosure and barrier over the work area to seal said areafrom human workers occupying adjacent areas; wherein the operators ofsuch drills or saws are required only to wear half-face respiratorsrather than protective clothing and cumbersome air line masks; whereinsavings realized in reduced set-up and take-down time effected by thetent-free nature thereof are further complimented by substantiallyreduced contamination of the areas that normally would be enclosed inthe tent enclosure currently used in the best available prior artmethods and thereby effectively reduces total clean-up time as well asresulting exposure of persons to the particulate contaminated air spreadthroughout the confines of the tented area; and more importantly becausethe instant invention confines generated particulate contamination toextremely small areas wherefrom the resulting concentrated contaminationis directly flushed to HEPA type filters, usually by means of a HEPAvacuum, actual exposure of the machine tool operators is verysubstantially reduced from that which they are exposed to when workingwithin the prior art tent type enclosures.

Still further and more general objects and advantages of the presentinvention will appear from the more detailed description set forthbelow, it being understood; however, that this more detailed descriptionis given by way of illustration and explanation only, and notnecessarily by way of limitation since various changes therein may bemade by those skilled in the art without departing from the true spiritand scope of the present invention.

DESCRIPTION OF THE DRAWINGS

The present invention will be better understood from a consideration ofthe following description taken in connection with the accompanyingdrawings in which:

FIG. 1 illustrates, in elevation, an embodiment of the instant inventionwherein drilling means is utilized in combination with first and secondcowling means.

FIG. 2 illustrates, in elevation, an embodiment of the instant inventionwherein sawing means is utilized in combination with third and secondcowling means.

FIG. 3 illustrates, in elevation, an embodiment of the instant inventionwherein a more preferred embodiment of the combination illustrated inFIG. 2 supra is utilized, which preferred embodiment has proven to bemore effective when the mounting board or like is already crowded withelectrical components. In such situations where there already exists arelatively high density of objects that might interfere with the vacuumhoses shown in the arrangement of FIG. 2, supra, it will be appreciatedthat the lower profile arrangement as shown in this FIGURE may be highlyuseful and desirable.

In the more specific descriptions of the FIGURES, infra, certaincomponents of the instant invention may be, or oftentimes are,substituted for one another. Accordingly, the index and numbering systemof components is arranged by means of three-digit designations, whereinthe first digit denotes the FIGURE number and the second and thirddigits the specific component identification. In this manner, forinstance, a second cowling means, illustrated in FIG. 1, can besubstantially identical with that shown in FIG. 2, thus, the designationthereof is 120 in FIG. 1 and 220 in FIG. 2. Likewise, the air filtrationunit, generally illustrated at 133 in FIG. 1, is generally illustratedas 233 in FIG. 2 and 333 in FIG. 3.

Referring now more specifically to FIG. 1, it will be appreciated thatdrilling means, generally illustrated at 101, is normally enclosed in ahousing, generally illustrated at 102, which housing means 102 isnormally provided with a handle, herein illustrated as modified pistolgrip 103. An actuating device, herein illustrating as trigger 104, isutilized to turn drilling means 101 on and off as desired. Although notshown, other features of drilling means 101 include either aself-contained battery pack and/or a power cord for connection withbuilding power. As is well appreciated by those skilled in the art, thedrive means, not shown, but usually contained within housing means 102of drilling means 101 usually terminates in drill bit chuck means,herein illustrated generally at 105, which chuck means 105 holds drillbit, generally illustrated at 106. As shown, drill bit 106 is positionedon the attack or target side of mounting board 107. First cowling means,which is utilized in combination with drilling means 101, is hereingenerally illustrated at 111. First cowling means 111 comprises firstmember 112, shown generally in sealable engagement with a portion ofhousing means 102 of drilling means 101. Second member 113 of firstcowling means 111 is shown in slidable engagement with first member 112and positioned with one generally open end thereof juxtaposed the targetside of mounting board 107. In the embodiment of the instant inventionshown in FIG. 1, both first member 112 and second member 113 of firstcowling means 111 is material constructed of transparent, rigid plastic,thusly the relative position of drill bit means 106 may be easilyascertained by the operator, not shown, of drilling means 101. It willbe appreciated that such depiction via transparent material here and inFIGS. 2 and 3, infra, also greatly facilitates illustration of theinstant invention. As illustrated herein, first member 112 is arrangedto be in slidable engagement inside second member 113 and in the mostpreferred embodiment of the instant invention both first member 112 andsecond member 113 are understood to be generally cylindrical in crosssection. It will be understood that the difference in dimension, betweenthe outside diameter of first member 112 and the inside diameter ofsecond member 113, may be predetermined with substantial discretion andlatitude so long as the cross sectional area, provided by thedifferences in such diameters, is not substantially greater than thecross sectional area of aperture 114, provided as herein shown in theside wall of second member 113, to provide flow communication withnon-collapsible vacuum hose 115 effected by releasable connecting means116. In operation and practice of the instant invention, it has beendetermined that when such differences in diameters are relatively small,so as to provide some degree of frictional resistance in the engagementof first member 112 within second member 113, positioning of thecombination of drilling means 101 and first cowling means 111 issubstantially facilitated, thereby enabling the operator to easilyaccomplish same while properly orientating drill bit means 106 relativeto the target position on mounting board 107. In the operation of drillbit 106 under conditions wherein the fit between first member 112 andsecond member 112 is fairly close as described above, it has been foundnecessary to provide means for ingress of sweep air in paths directingsame over chuck means 105 and thence over that portion of the drill bitfurthest removed from engagement with mounting board 107. This provisionhas been found to be important to the practice of the instant inventionin order to ensure substantially no buildup of drill cuttings or dustover that shank portion of bit 106 and/or chuck means 105. Accordingly,relatively small sweep air apertures 117 and 118 are shown provided inthe wall portion of first member 112 and located at or near itsengagement with housing 102. It has been found that sweep air apertures117 and 118 are best located approximately 180 degrees apart and areprovided with a diameter of approximately 1/8 inch. It will beunderstood, of course, that an additional plurality of like aperturescan be employed or alternatively the sealable engagement of first member112 with housing 102 can be disposed in a manner not shown, whereinsufficient quantities of sweep air can be introduced through cut-outportions thereof. Second cowling means 120, herein shown for conveniencealso as material constructed of transparent plastic, is adapted forarrangement on the side of mounting board 107 opposite to its targetside. For purposes of convenience of illustration and description,second cowling means 120 is also generally cylindrical in cross sectionand has a diameter generally similar to the diameter of second member113 of first cowling means 111. Depending, of course, on the population,density, and relative size of components mounted on board 107, it may beconvenient to provide second cowling means with a smaller or largerdiameter relative to the diameter of second member 113 of first cowlingmeans 111. Thusly, when a plurality of apertures are to be formed inmounting board 107 according to a predetermined template, it may beconvenient to provide second cowling means 120 with a cross-sectionalarea conveniently large enough to encompass the whole of said templatewhereby such second cowling means so provided can be temporarily fixedas by application of duck tape to the opposite or non-target side ofmounting board 107. Depending on the population density on the targetside of mounting board 107, the profile of the arrangement shown in thisFIG. 1, particularly that effected by releasable connecting means 116and vacuum hose 115 may tend to interfere with the placement of secondmember 113. Accordingly, the direction of sweep air through first member112 and thence through second member 113 can be reversed by utilizingone or more apertures similar to 114 as weep air inlet means, andproviding or disposing two or more relatively small non-collapsiblevacuum hoses, not shown, in connection with apertures provided at ornear those herein indicated by 117 and 118. The resulting arrangement oftwo such relatively small non-collapsible vacuum hoses would present aprofile somewhat similar to that illustrated in FIG. 3, infra, byapertures 354 and 356 in flow communication with vacuum hoses 355 and357. It is to be understood that this reversed arrangement of sweep airis not the most preferred for effecting the efficient operation of drillmeans 101, but does present a workable alternative embodiment. Aselsewhere described and herein understood, although first member 113 offirst cowling means 111 is open at both ends thereof, second cowlingmeans 120 is open only at the end thereof which is adapted for contactwith the side of mounting board 107 opposite to the target side thereof.The other end of second cowling means 120, herein generallycylindrically shaped, is closed thereby providing a generally cuppedshaped member which is provided as herein shown with aperture 121 in theside wall thereof, adapted for flow communication with non-collapsiblevacuum hose 122. As is also elsewhere described, the flow connectioneffected between aperture 121 and vacuum hose 122 is normally more orless permanent in nature, whereas the flow connection effected ataperture 114 in second member 113 with non-collapsible vacuum hose 115may preferably be in arrangement with provides for disconnecting, byreleasable connecting means 116 of non-collapsible vacuum hose 115therefrom such that non-collapsible vacuum hose 115 may be later flowconnected to a later mentioned third cowling means shown in FIGS. 2 and3, infra, either directly as shown in FIG. 2, or through utilization ofmanifold means as shown in FIG. 3. As noted, such connection ordisconnection may be effected by releasable connecting means 116. Itwill also be understood that in most instances mounting board 107,herein shown to be perhaps only one or two feet on edge, usually is muchlarger and both disposed and dimensioned so that the operator, notshown, of drilling means 101 can neither see around nor reach the sideopposite the target side, i.e., that which is first engaged by drill bitmeans 106. Accordingly, it is normally necessary for an operator helper(not shown) to position himself on such opposite side of mounting board107 to secure cowling means 120 in temporary engagement with thatnon-target side of mounting board 107. By prearrangement of coordinatesrelative to landmarks on mounting board 107 such as, for instance, majorcomponents already mounted thereon or dimensions from edges thereof, theapproximate location of the "punch-through" of drill bit means 106 canreadily be ascertained by the operator helper to a degree of sufficientprecision whereby second cowling means 120 can be temporarily positionedby, for instance, hand holding to effect practice of the instantinvention. As shown, non-collapsible vacuum hoses 115 and 122 are inflow connection by means of optional manifold 130 with non-collapsiblevacuum hose 131, which in turn is flow connected by means of optionaladapter 132 with the filtration unit, generally herein illustrated at133 and provided with blower means and a HEPA type filter, bothgenerally illustrated at 134. It will, of course, be appreciated thatfiltration unit 133 is normally placed in operation by means ofswitching means, not shown, and a power supply thereto, also not shown.Accordingly, when it is desired to produce one or more apertures inmounting board 107 or the like, the arrangement herein shown is utilizedwhereby the emissions of particulate contamination resulting therefromare contained within first cowling means 111 and second cowling means120 and exhausted therefrom through non-collapsible vacuum hoses 115 and122 through the arrangement shown for trapping of such finely sizedparticulate emissions by means of the HEPA filter, generally shown at134. Thusly, neither the work area immediately adjacent mounting board107 or the area generally surrounding same in which the operatorsnormally function needs to be tented. Furthermore, the human operatorand operator helper are not required to wear protective clothing andfull face respiratory devices, it having been determined in thedevelopment of the instant invention that the more comfortable half-facerespirators rather than cumbersome air line masks provide more thansufficient protection.

Referring now more specifically to FIG. 2, therein is shown anarrangement of an embodiment of the instant invention which isoftentimes utilized in sequence with the combination shown and describedin FIG. 1, supra, wherein subsequent to the punching through or drillingof one or more holes in the mounting board therein described, anaperture is cut by means of a saw blade or the like inserted into one ormore of such holes, or apertures. For instance, when a generallyrectangular aperture needs to be provided it is oftentimes convenient todrill four hours generally defining the corners thereof and sawingtherebetween. It will be appreciated, however, that the embodiment shownin this FIGURE as well as that in FIG. 3, infra, may in some instancesbe utilized wherein apertures already exist or the sawing commences froma position such as an outside edge of the board, wherein engagement ofthe blade is readily effected without a drilling operation sequencedprior thereto. Accordingly, one embodiment of the sawing means usedherein oftentimes takes the form of a saber saw, as generallyillustrated at 241. Saw means 241 is generally enclosed in housingmeans, or more simply housing 242 and may be provided with an actuatingdevice such as trigger 244. Such a device may be provided with neckedportion 245 located between the main portion of saw means 241 and baseplate member 246, which base plate 246 is positioned a predetermineddistance therefrom by means of base plate holder 247. Saw blade 248 isarranged to travel or reciprocate beyond the bottom portion of baseplate 246, which in the above illustration, is shown urged against thetarget side of mounting board 207. As is customary in saber-type devicesand as noted above, saw blade 248 extends a substantial distance beyondbase plate 246. In practice of the instant invention, third cowlingmeans, generally shown at 249, is positioned in sealable engagement withsaw means 241 and, as shown in this illustration, conveniently engagedwith necked portion 245 thereof, with the opposite and open end thereofurged against the target side of mounting board 207 in an arrangementwhereby both base member 246 and a major portion of saw blade 248 areenclosed thereby. Although the cross sectional configuration of cowlingmeans 249 may be generally circular as oftentimes is its counterpart, towit, cowling means 111 in FIG. 1, supra, because the direction of cut inthis device is essentially 90 degrees from that of drill means 101 inFIG. 1, supra, it has been found more convenient to make the crosssectional configuration of cowling means 249 and for that matter itscounterpart 349 in FIG. 3, infra, generally rectangular in shape and ofa size sufficient to fit over base plate 246, which itself is normallyrectangular. In this FIGURE, both cowling means 249 and 220 are shown intransparent material construction whereby all of the components fittedthere within are readily discernible in the respective elevations. Asnoted elsewhere, in order to facilitate orientation of saw blade 248relative to the cut to be made in mounting board 207 and also to ensurethat cowling 220, located on the other side of mounting board 207, isproperly positioned relative to the target, such transparent materialconstruction is a requirement of the instant invention, it beingunderstood that in the most preferred embodiments all of said cowlingsare transparent material constructed, as opposed to those instanceswherein it is deemed desirable, because of other considerations, toconstruct only portions of said cowlings of transparent materials. Itwill, of course, be further understood that the arrangement shown isnormally effected after an aperture, either a drilled hole or cut slit,is provided in mounting board 207, one such hole herein generallyillustrated by broken lines 251 and 252, to thereby accommodate theportion of saw blade 248 which is shown to extend beyond the bottomportion of base plate 246. As referenced above, some of the embodimentsof this invention are provided with releasable connecting means betweenthe apertures provided in the cowlings and their respectivenon-collapsible vacuum hoses. Accordingly, in the instant illustration,it will be appreciated that aperture 214, provided in the side wall ofcowling means 249, is in flow connection with non-collapsible vacuumhose 215, which vacuum hose 215 may be in interchangeable,interconnecting relationship via releasable connecting means 216, withaperture 114 in FIG. 1, supra. Thusly, vacuum hose 115 in FIG. 1 can bethe same hose represented here in FIG. 2 as 215. Likewise, cowling 220and aperture 221, provided in the side wall thereof, which aperture 221is in flow connection with non-collapsible vacuum hose 222, oftentimesare the same device illustrated and described in FIG. 1, supra, ascowling 120, aperture 121, and non-collapsible vacuum hose 122. In viewof the foregoing, it should be appreciated by those skilled in the artthat the description and functioning of the remaining elements in thiscombination, to wit, optional manifold 230, vacuum hose 231, andfiltration unit generally illustrated at 233, having optional attendantadapter means 232, as well as a HEPA type filter and blower shown at 234are as described above for the respective counterparts in FIG. 1.

Referring now more specifically to FIG. 3, therein is shown anarrangement of the instant invention similar to that described in FIG.2, supra, but with modifications to the relative positions of the vacuumhoses attendant the respective cowlings to provide units which may befitted into tighter or smaller spaces on mounting board 307.Accordingly, the elements of the sawing means, the respective cowlings,and that portion of the particulate removal system from the juncture ofthe two main non-collapsible vacuum hoses into the aforementionedmanifold means, and thence to and through the filtration unit aresubsequently as described in FIG. 2, supra. In the instant embodiment, amodification has been made to cowling 320 by locating aperture 321 inflow communication with vacuum hose 222 in the closed end wall thereof,rather than in the side wall, as shown at 121 and 221 of FIGS. 1 and 2,respectively. In addition, cowling 349, which is in sealable engagementwith saw means 341, has two apertures 354 and 356 provided in or nearthe end wall or portion thereof furthest removed from the open end, theaperture of which open end defines a plane generally coincident with thebottom portion of base member 346. As shown, apertures 354 and 356 arein flow connection with non-collapsible vacuum hoses 355 and 357,respectively, both of which optionally union in manifold 358 to whichnon-collapsible vacuum hose 315 is flow connected via releasableconnecting means 316. As noted supra, vacuum hose 315 may or may not beidentical to hose 215 or 115 of FIGS. 2 and 1, respectively. In such anarrangement, it will be appreciated that the diameter of vacuum hoses355 and 357 may be smaller than that of 315 to thereby allow the overalldimension of cowling 349 to likewise be reduced in size so as to permitfitting into tighter portions of mounting board 307 on the attack sidethereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention comprises a new, simple, effective, efficient andsafe method and means for effecting protection of human operatorsagainst the deleterious health hazards normally caused by the effects ofairborne asbestos fibers and certain other fine particulatecontamination. The instant invention relates to limiting occupationalexposure to asbestos, either of the chrysotile or the amphiboles type,as well as other particulates characterized as carcinogens and deemed bytoxicologists as being responsible for effecting a high incidence oflife-threatening lung ailments--in particular lung cancer andmesothelioma, a fatal cancer that appears to strike only those who haveinhaled asbestos or other similar fiber. More particularly, it relatesto methods and means for efficiently and effectively containing andlowering the level of such particulate contamination in an area that isenvironmentally in communication with a source generating a high levelof a variety of particulate contamination harmful to the human bodyeither on a short term or long term basis. Still more particularly, itrelates to the practice of a technique, as well as equipment attendanttherewith, which is substantially suitable to aid in the protection ofthe persons actually in an area generating a high level of suchparticulates such as, for instance, where ebony-asbestos boards must bedrilled or sawed for the removal, mounting, or other installation ofelectrical equipment components thereon, which components necessarilyfunction best because of the electrical insulation characteristicsexhibited by such asbestos containing substrates. More specifically, itrelates to the use of specially designed apparatus and involves the useof a plurality of, most preferably, transparent cowling means which arespecially designed for operative association with a variety of drillingand/or sawing means, including commercially available hand held drillsand saber saws used in the machining of such asbestos containingmaterials.

In the most preferred embodiment of the present invention, three suchcowling means are utilized. More specifically, a first and secondcowling means are used in operative association with the drill and acombination of said second cowling means and a third cowling means areused with the saw. The first cowling means generally comprises twomembers adapted to be in relative movement association with one anotherduring the drilling operation and disposed generally between the drillhousing and the target side of the mounting board or other like asbestoscontaining material. The second cowling means is generally disposed onthe side of the mounting board, which is opposite to said target sideand therefore separated from said first cowling means by the thicknessof said mounting board. The third cowling means is utilized in operativeassociation with the saw. During practice of the present invention, atany given time, at least two and sometimes all three of such cowlingmeans are operatively associated with at least one filtration unit flowconnected therewith and with a blower to pull air into the speciallydesigned cowlings and thence into the filtration unit wherefrom theresulting filtered air is exhausted to the atmosphere, with said cowlingmeans being connected thereto usually by means of non-collapsible vacuumhoses affixed, either permanently or releasably connected, usually (butnot always) to the side wall thereof.

The at least one filtration unit normally utilized in the practice ofthe instant invention is a HEPA filter, preferably of the typecharacterized as having a 99.99 percent efficiency of 0.3 micronmaterial. Such filter is used in conjunction with a high-performancevacuum cleaner disposed in operative association therewith and providedwith a blower unit characterized by a propensity to develop and providesubstantial airflow and pressure differential through and across saidHEPA filter unit.

In order to accommodate the travel of the drill bit, the first cowlingmeans operatively associated with said drilling means comprises twomembers slidably disposed relative to one another, with the first memberthereof being more or less substantially fixed relative to the drillhousing and the second member adapted to be fitted temporarily to thetarget side of the mounting board or other member to be drilled. In thepreferred embodiment of the instant invention, said second member ofsaid first cowling means is provided with means for effecting the flowconnection with said at least one filtration unit. Normally a secondcowling means, also flow connected to said filtration unit, isoperatively associated with the instant apparatus and is fittedtemporarily (usually hand held by the operator helper) to the side ofthe material which is opposite to that first targeted for engagementwith the drill bit of said drilling means. A third cowling means, alsoflow connected to said filtration unit, is operatively associated withthe sawing means which sawing means may be utilized after holes aredrilled in the target mounting board, or the like, and is generallyfixed relative to the housing thereof. One end of said third cowlingmeans is open to fit over the base plate of the saw, normally of thesaber type, and defines a plane substantially parallel to the plane ofthe target board. Likewise, one end of the second cowling is generallyopen ended, with the plane defined thereby also disposed generallyparallel to the major planes of the mounting board, or like. It isimportant that all three cowlings be constructed of material that isstiff, and/or resilient enough to withstand the substantial pressuresthat may be developed therearound due to the pressure differentialsdeveloped by operation of the associated filtration unit. It is alsoimportant to the efficient and effective operation of the instantinvention that at least portions of all three such cowling members orunits be constructed of material which is transparent, thereby enablingthe drill or saw operator to observe the positions of either the drillbit or saw blade relative to the target, and to enable such operator toeasily and readily effect proper orientation and/or positioningtherebetween. It will also be appreciated that provisions may be madesuch that the flow connections with the at least one filtration unit andthe first and third cowling means are arranged or constructed such thatthey are, or can be removably connected therefrom. In such manner, afterthe holes are drilled and the drill is put aside, the vacuum hoseconnected to the second member of the first cowling means may be removedtherefrom and connected, with the aid of the suitable releasableconnecting means to said third cowling means. Also, in the preferredembodiment of the instant invention, the vacuum hose and the secondcowling means, which is normally used on the backside of the board orplate to be drilled and/or sawed to capture particulate material forcedtherethrough by either the drill bit or blade, is utilized incombination with both the drill land the saw, or other machine tool.Accordingly, there usually is no need to effect a disconnection betweensaid second cowling means and said at least one filtration unit. Thus,either three separate vacuum hoses may be used, or more preferably, twovacuum hoses are utilized with a switching between the first and thirdcowling means being effected through the use of releasable connectingmeans, if and when it is deemed desirable to follow the drillingprocedure with a sawing operation.

While I have shown and described particular embodiments of my invention,modifications and variations thereof will occur to those skilled in theart. I wish it to be understood, therefore, that the appended claims areintended to cover such modifications and variations which are within thetrue scope and spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:
 1. An improved, tent-free particulate contamination controlsystem for effecting protection of human operators against thedeleterious health hazards normally caused by the effects of certainairborne fine particulate contamination, including asbestos fibers, saidhuman operators having occasion to work in an are that isenvironmentally in communication with a source, including cutting means,for generating a high level of such particulate contamination, saidsystem comprising:cutting means for effecting cutting of at least oneplate member; said plate member generally having a determinable targetside and a side opposite to said target side and comprising materialsthat are characterized by a readily determinable content of materialthat has been determined to be carcinogenic when inhaled by humans andfurther characterized as being friable; said cutting means including sawblade means, saw blade drive means, base member means having a bottomportion thereof, and saw housing means for generally enclosing at leasta portion of said saw blade drive means; first cowling means comprisingan elongated, hollow member adapted at one end thereof for sealingengagement with said saw housing means and an aperture at the other endthereof, said aperture defining a plane substantially parallel to andjuxtaposed the target side of said plate member; second cowling meanscomprising an elongated, hollow member being generally closed at one endthereof and an aperture at the other end thereof, said aperture defininga plane substantially parallel to and juxtaposed the side of said platemember opposite to said target side; and at least one filtration unitoperatively associated with both said first and second cowling means andflow connected therewith by means of non-collapsible vacuum hoses; saidat least one filtration unit operatively associated with blower meansadapted to pull air into said cowling means and thence into the at leastone filtration unit wherefrom the resulting filtered air is exhausted tothe atmosphere.
 2. The improved, tent-free particulate contaminationcontrol system of claim 1, wherein the bottom portion of said basemember means is generally coincident said plane defined by said apertureof said first cowling means.
 3. The improved, tent-free particulatecontamination control system of claim 2, wherein said first and secondcowling means is non-collapsible material constructed to resistdeformation attendant the pressure differential effected by operation ofsaid at least one filtration unit, with at least a portion of said firstcowling means being transparent material constructed to facilitateorientation, by the cutting means operator, of the saw blade meansrelative to a target position on said target side of said plate member.4. The improved, tent-free particulate contamination control system ofclaim 3, wherein said at least one filtration unit operativelyassociated with said first and second cowling means is flow connectedtherewith through the walls thereof.
 5. The improved, tent-freeparticulate contamination control system of claim 4, wherein theperipheral configuration of said first cowling means is complementary tothe peripheral configuration of said base member means.
 6. A device foreffecting tent-free particulate contamination control and protection ofhuman operators against the deleterious health hazards normally causedby the effects of certain airborne fine particulate contamination,including asbestos fibers, said human operators periodically havingoccasion to work in an area that is environmentally in communicationwith a source, including cutting means, for generating a high level ofsuch particulate contamination, said device comprising:cutting means forcutting at least one plate member; said plate member having adeterminable target side and a side opposite to said target side andcomprised of materials that are characterized by being carcinogenic wheninhaled by humans and further characterized as being friable; saidcutting means comprising:saw blade means, saw blade drive means, basemember means having a bottom portion thereof, and saw housing means forgenerally enclosing at least a portion of said saw blade drive means; afirst cowling comprising:an elongated, hollow member adapted at one endthereof for sealing engagement with said saw housing means and beingprovided with an aperture at the other end thereof, said aperturedefining a plane substantially parallel to said plate member and adaptedfor temporary engagement with the target side of said plate member; asecond cowling comprising:a generally elongated and hollow member beinggenerally closed at one end and being provided with an aperture at itsother end, said aperture defining a plane substantially parallel to saidplate member and adapted for temporary engagement with the side of saidplate member opposite to said target side; and at least one filtrationunit comprising:a first non-collapsible vacuum hose operativelyassociated with said first cowling, a second non-collapsible vacuum hoseoperatively associated with said second cowling, a HEPA type filter flowconnected with said first and said second non-collapsible vacuum hose;and a blower means operatively associated said filter and adapted topull air into said cowling means and thence into said filter wherefromthe resulting filtered air is exhausted to the atmosphere.
 7. A deviceaccording to claim 6 wherein said first and second cowling isnon-collapsible material constructed to resist deformation attendant thepressure differential effected by operation of said at least onefiltration unit, with at least a portion of said first cowling meansbeing transparent material constructed to facilitate orientation of saidcutting means relative to the target position on the target side of saidplate member.
 8. A device according to claim 7 wherein the bottomportion of said base member means is generally coincident said planedefined by said aperture of said first cowling.
 9. A device according toclaim 8 wherein the peripheral configuration of said first cowling iscomplementary to the peripheral configuration of said base member means.